Fernandez, who is ranked the organization's No. 1 prospect by MLB.com, has already developed a close friendship with Alvarez.
"I was talking with Henderson," Fernandez said. "He was like, 'Oh, they're going to kill you. They're going to hit the ball 450 feet.' I was like, 'No they won't.' All those guys were messing with me, too."
When the game started, it was Fernandez who ended up with something cheer about.
The hard-throwing right-hander threw 1 1/3 innings of scoreless relief in the Marlins' 6-5 walk-off victory.
Fernandez, ranked seventh on MLB.com's Top 100 Prospect list, has not pitched above Class A. He is expected to open the season at Double-A Jacksonville.
Facing an imposing lineup was one of the biggest thrills of his career.
"It came out pretty good," Fernandez said. "That was a big step, too. That's big. I threw 1 1/3 innings, but you know, there was a lot of doubt."
The doubt being from the evaluators wondering when he will be big league ready.
"Is he ready? Can he pitch up here?" Fernandez said. "I pitched. I had a lot of fun out there. It was amazing to pitch against those guys out there. That's an amazing team."
Fernandez entered in relief of Wade LeBlanc with two outs in the third inning. His first pitch ran up and in on Martin Prado, but Fernandez settled and retired Prado on a fly ball to center.
Fernandez's fastball ranged from 92-95 mph. In the fourth inning, he struck out Marco Scutaro.
"They've got an amazing team," Fernandez said. "All those guys, I met them today. They were nice, very humble. That's very important, they are superstars."